Vertical wind turbine with controlled tip-speed ratio behavior, kit for same, and method for operating same

ABSTRACT

A vertical wind turbine that includes a plurality of vertical vanes which is secured to a vertical vane axis so as to be rotatable independently of one another about a respective vane rotational axis and which are rotatably mounted about a vertical rotor rotational axis on a common circular path. A method for operating a vertical wind turbine, in which method pitch angles of vertical wind turbine vanes driven about a respective vertical vane axis are specified. The vertical wind turbine is operated in a particularly efficient and material-preserving manner by control of the pitch angles, at least in a partial load mode of the vertical wind turbine, such that the vanes rotate with a substantially constant tip-speed ratio.

TECHNOLOGICAL BACKGROUND

The present invention relates to a vertical wind turbine, as well as akit for a vertical wind turbine, and a method for operating a verticalwind turbine according to the preambles of claims 1 and 15,respectively.

Vertical wind turbines with active blade control are known from theprior art. WO 2015/185299 A1 on behalf of the applicant discloses avertical wind turbine with vertical blades, that are each driven by aservomotor via a transmission into a predetermined rotational positionaround their respective axis of rotation, which position can be changedat any time; virtual cam disks are provided, which respectivelydetermine the course of the blade angle by means of the position of theblade on the circle of revolution, and wherein the active control iscarried out in accordance with the virtual cam disks.

Further, European patent EP 2 235 365 B1 on behalf of the applicantrelates to a wind turbine with at least one rotor, which can be rotatedaround a vertical axis and which, between two horizontal bearing planesdisposed at a distance on top of each other, comprises a plurality ofrotor blades, which are disposed uniformly distributed on acircumferential circle and can each be pivoted around a vertical pivotaxis and the pivot range of which is delimited on both sides by a limitstop.

Furthermore, the document U.S. Pat. No. 3,902,072 A discloses a windpowered generator with a horizontal, rotating platform on the outercircumference of which a plurality of vertical blades is positioned,which all revolve coaxially around a central axis and each rotate aroundan individual axis. The rotation of the vertical blades depends onchanges in the wind direction and wind speed and the rotation of eachindividual blade is controlled so that for 3/4 of the rotation path ofthe platform, power is drawn from the wind, while for the rest of thepath, the blades are adjusted so that they offer minimal resistance tothe wind. The blades are controlled by means of a central transmissionmechanism with a shared servomotor.

The document U.S. Pat. No. 4,410,806 A describes a vertical wind turbinewith a rotating structure, which includes a series of rotatable verticalblades positions of which are controlled to maintain a constant rotationspeed of the rotating structure, when wind speed is sufficient. Amicroprocessor controller processes information about the wind speed,wind direction, and rotation speed of the rotating structure andproduces an electrical signal for adjusting the blade position. Thecontrol system for the wind turbine includes electrical blade actuatorsthat modulate the blades of the rotating structure. Blade modulationcontrols the angle of attack, which in turn determines the rotationspeed of the rotor. A wind speed sensor provides data for starting orstopping the system and a wind direction sensor is used to keep theblade flip region at 90° and 270° relative to the wind direction. Thecontrol system is designed to maintain constant rotation speed at windspeeds of between 19 and 40 miles per hour.

The document U.S. Pat. No. 4,494,007 A discloses a vertical windturbine, wherein the orientation of the blades revolving around a commoncentral axis is controlled by a tail vane by means of a shared mechanismduring their rotation around the central axis such that if the windspeed changes, the rotation position of the blades is changed.

The document U.S. Pat. No. 4,609,827 A describes a vertical wind turbinewith rotor vanes that are airfoil-shaped. A positive and synchronousvane orientation system is controlled by a mechanism located exterior toits rotor.

Finally, in “Vertical Axis Wind Turbine with Individual Active BladePitch Control”; College of Mechanical and Electrical Engineering; HarbinEngineering University; Harbin, China; 2012 IEEE, Lixun Zhang, YingbinLiang, Erxiao Li, Song Zhang, and Jian Guo describe a vertical windturbine with individually active blade control, wherein servomotors aremounted on the arms supporting the blades and each by means of a beltdrive, are intended to perform a pitch angle adjustment of the blades inaccordance with their azimuth angle.

In “H-Darrieus Wind Turbine with Blade Pitch Control”; InternationalJournal of Rotating Machinery, vol. 2009, Ion Paraschivoiu, OctavianTrifu, and F. Saeed address a variation of the pitch angle of the bladesof a vertical wind turbine in accordance with the azimuth angle in orderto maximize a torque output by the rotor of the vertical wind turbine.

In “A Straight-bladed Variable-pitch VAWT Concept for Improved PowerGeneration”; ASME 2003, Wind Energy Symposium, vol. 2003, pp. 146-154;January 2003, Y. Staelens, F. Saeed, and I. Paraschivoiu describeexperiments for improving the performance of vertical wind turbines withblades, a pitch angle of which is variable. At each blade, thetangential force should be optimized by varying the pitch angle in therespective rotational position in accordance with the azimuth angle.Different blade profiles are studied.

In vertical wind turbines that are known from the prior art, it isdisadvantageous that the blade control and blade drive do not enable asatisfactory energy yield and reasonable efficiency. In addition, theblade drive consumes too much energy and is susceptible to wear, whichminimizes the efficiency and service life of the systems in anunsatisfactory way.

DISCLOSURE OF THE INVENTION

One object of the invention is to avoid at least some of thedisadvantages of the prior art. In particular, the efficiency andservice life of vertical wind turbines should be improved in comparisonto the prior art. This object is achieved by the features of theindependent claims 1 and 15.

In particular, the disadvantages of the prior art are overcome by meansof a vertical wind turbine according to the invention with a pluralityof vertical blades, which are each fastened to a respective verticalblade axis such that they are pivotable independently of one anotheraround a respective blade rotation axis, and are supported rotatable ona common circular path around a vertical rotor rotation axis, thevertical wind turbine being configured to control a pitch angle of theblades at least in a partial load mode of the vertical wind turbine suchthat the blades rotate with an essentially constant tip speed ratio λ.

With a method according to the invention, the disadvantages of the priorart are overcome by predetermining pitch angles of vertical blades ofthe vertical wind turbine, which blades are driven around a respectivevertical blade axis, wherein the pitch angles, at least in a partialload mode of the vertical wind turbine, are controlled such that theblades rotate with an essentially constant tip speed ratio λ.

The solution according to the invention has the advantage that the tipspeed ratio λ can be selected such that the angle between the incidencevector of the wind and the rotor blade chord (the so-called pitch angleor also referred to as the angle of attack) does not exceed a value atwhich the flow separates from the profile. The tip speed ratio λ isdefined by the ratio of the rotational speed of the rotor to the windspeed. Up to a nominal speed, vertical wind turbines according to theinvention have a tip speed ratio λ of 2 to 2.5, preferably approx. 2.3,which is determined by a circumferential speed of the blades of approx.27.6 m/s at a wind speed of 12 m/s during nominal operation(λ=27.6/12=2.3).

The higher the tip speed ratio, the smaller the angle of attack relativeto the profile. In reality, this means that vertical wind turbinesaccording to the prior art are generally operated with tip speed ratiosλ of greater than 4. This necessarily results in high rotation speeds oralternatively to high rotor radii in order to achieve thecircumferential speed that is required for the tip speed ratio. Highcircumferential speeds in turn increase parasitic losses, which arecaused by the aerodynamic drag of rotor arms and guys, for example. Suchlosses influence the energy output by the cube of the circumferentialspeed.

A pitch control of the blades according to the invention helps to keepthe tip speed ratio as optimally constant as possible and compensatesfor negative effects of strongly and quickly changing wind conditions.Thereby, an optimal energy yield, particularly in partial loadoperation, is achieved. Consequently, vertical wind turbines accordingto the invention make it possible to utilize wind energy in aneconomically efficient way even in locations with widely varying windconditions.

In addition, high circumferential speeds contribute to a high noiseemission and to high centrifugal accelerations. Through a continuouscontrol of the rotor blades of the kind that is implemented in verticalwind turbines according to the invention, in principle any tip speedratio can be used with the optimal angle of attack. In other words, astall can be avoided even with low tip speed ratios. It is thus possiblefor the optimal operating range to be evaluated in a way that takes intoaccount parasitic resistances.

Numerical simulations with a DMS model (double multiple stream-tube) forvertical wind turbines according to the invention in accordance with anexemplary embodiment show a maximum energy yield at a tip speed ratio offor example λ=2.3. Including geometrical dimensions of vertical windturbines according to the invention, this yields circumferential speedsof approx. 100 km/h, which leads to significantly lower noise emissionsthan in conventional horizontal wind turbines and vertical wind turbinesthat are known from the prior art because the circumferential speedaffects the acoustic power to the sixth power.

Furthermore, in connection with a wind farm efficiency of vertical windturbines, which is approx. 20% and is thus more advantageous than a windfarm efficiency of horizontal wind turbines, which is approx. 10%,vertical wind turbines that are configured and operated according to theinvention can be operated more efficiently and economically thanhorizontal wind turbines, particularly in wind farms, or more preciselystated, can be operated at twice the wind farm efficiency. In addition,unlike horizontal wind turbines, vertical wind turbines according to theinvention can be operated in a power range of for example 750 kWgenerator output power, which is ideal for the rapidly growing sector ofthe “distributed wind market” in which environmentally friendly andsocially responsible solutions are very relevant (populated areas,logistically challenging wind locations).

In addition, vertical wind turbines according to the invention have anadvantageous wake behavior. Since the blades are held in their angularposition in a variable manner by means of the pitch motors, which helpsprevent stalls, this minimizes turbulence in the wake. A resulting lowturbulence intensity in the wake allows for shorter distances betweenvertical wind turbines according to the invention and thus furtherimproves their wind farm efficiency.

As a result of small and/or lightweight components, in contrast tohorizontal wind turbines, it is possible to set up vertical windturbines without heavy transport even in difficult terrain. In normalterrain, all of the components of a vertical wind turbine (even heavyones) can be transported using a conventional truck without specialtransport. In mountainous terrain, the components can be transported bya light helicopter and the few heavy components can be transported by anoff-road vehicle.

Vertical wind turbines according to the invention can be installed usinga self-assembly system without the use of additional heavy-duty cranes.The self-assembly system includes a central crane that grows along witha tower or tower system of a vertical wind turbine according to theinvention and heavy-duty lifting rollers that are positioned in thetower. All of the heavy main components can be hoisted to theirrespective installation heights by means of a mobile cable winch on theground and deflection sheaves in the tower.

For repair-related disassembly and assembly work on the rotor blades andblade bearings, only a small crane is temporarily positioned at the verytop of the respective rotor arm with the aid of a helicopter. For simplemaintenance and repair work on the rotor, the rotor is locked inposition by positive-fit engagement. In the case of rotor bearingdamage, generator damage, or transmission damage, disassembling therotor does not require removal thereof. When stopped, it is mechanicallysecured to a lifting device on the tower and a thrust bearing supportingthe rotor is thus freed of the rotor load. This securing can withstandgale forces. The components possibly requiring repair can then belowered without a crane, using a cable winch and deflection sheaves inthe tower and can be directly loaded onto a truck at the bottom.

Finally, with regard to their environmental impact, the vertical windturbines according to the invention are also advantageous in that thesilhouette of their vertically oriented rotor is more visible to birdsand bats than a horizontally rotating three-blade rotor. In addition, ata maximum of 100 km/h, the rotor blade speeds are significantly lowerthan with horizontal wind turbines in which blade tip speeds of 300 to400 km/h occur. In contrast to horizontal wind turbines, the relativelyslowly rotating rotor system of a vertical wind turbine according to theinvention has a calm shadowing and a small ice throwing range. Theappearance of a vertical wind turbine according to the invention, withits predominantly vertical lines, integrates well into the surroundinglandscape.

The solution according to the invention can be arbitrarily enhanced andfurther improved by means of the following embodiments, which are eachadvantageous in and by themselves; a person skilled in the art willeasily recognize in a clear and unambiguous way that apparatus featuresof a vertical wind turbine according to the invention constitute thebasis for corresponding steps of a method according to the invention andvice versa.

According to a first further embodiment of a vertical wind turbineaccording to the invention, the vertical wind turbine is designed tooperate in the partial load mode in a range of wind speeds that at leastpartially lie between 3 and 12 m/s. Such a partial load range issuitable for both inland and coastal sites and ensures a high energyyield as well as a relatively large number of full load hours per year.With a low starting speed of 3 m/s, the partial load range also ensuresthat a vertical wind turbine according to the invention is able tosupply power even in a light wind.

According to another embodiment, the constant tip speed ratio amounts tobetween 2 and 2.6, preferably between 2.2 and 2.4, and most preferablyessentially 2.3. A value range of this kind for the constant tip speedratio results in relatively low rotation speeds of the rotor andtherefore relatively low blade speeds. As a result, a vertical windturbine according to the invention, as already mentioned above, can beoperated with advantageously low environmental influences.

According to another embodiment, the vertical wind turbine is configuredto control the pitch angle so that in a nominal operation mode of thevertical wind turbine, the blades rotate with a variable tip speedratio. A pitch control according to the invention can thus contribute tolimiting the output of a vertical wind turbine according to theinvention. This prevents damage to the material of a vertical windturbine according to the invention and thus reduces wear on it andextends its service life.

According to another embodiment, the vertical wind turbine is configuredto control the pitch angle so that in the nominal operation mode, theblades rotate at an essentially constant nominal speed. As a result, therotor rotates in a nominal speed range. This helps to avoid load peakson components of the vertical wind turbine and therefore helps toprevent damage to the material of a vertical wind turbine, reduce wear,and increase service life.

According to another embodiment, at a first cut-out wind speed v₃ of thevertical wind turbine, the variable tip speed ratio λ amounts to between1 and 1.8, preferably between 1.3 and 1.5, most preferably essentially1.38. For example, the cut-out wind speed v₃ can be in the range of 20m/s. Particularly at such a relatively high wind speed, the relativelylow value range of the variable tip speed ratio helps to keep thecircumferential speed of the blades as low as possible and thus toensure that a vertical wind turbine according to the invention is veryenvironmentally friendly.

According to another embodiment, the vertical wind turbine is configuredto control the pitch angle in a start-up mode so that starting from aresistance mode with tip speed ratios of λ≤1, the blades transition intoa fast mode with tip speed ratios of λ>1. It is thus possible,particularly when starting the vertical wind turbine from a rotorstandstill, to make optimal use of the energy absorbed by the bladesbased on their wind resistance and to maximize a start-up torque on therotor. As soon as the rotor has reached a certain rotation speed, asmooth transition to the fast mode of the blades can be carried out.This helps to shorten the overall start-up times of a vertical windturbine according to the invention and thus helps to increase the energyyield.

According to another embodiment, the control of the pitch angle is basedon at least one cam disk, which determines the pitch angle in anessentially continuous manner for an entire rotation of the rotor. Acontinuous determination of the pitch angle enables the gentlest,smoothest possible control and regulation of a vertical wind turbineaccording to the invention with the least number of parameter jumps ofthe kind that can occur when pitch angles are predetermined in rough,discrete steps. Different cam disks can be specified for different windspeeds. Each of the cam disks can be optimized with regard to therespective wind speed and with regard to the resulting flow conditionsat the blades.

According to another embodiment, a maximum value of the pitch angle forwindward positions of the blade is generally greater than for leewardpositions of the blade, with respective regard to the rotor rotationaxis. In other words, for azimuth angles of less than 180°, the pitchangle can generally be less than for azimuth angles of between 180 and360°. The pitch control thus takes into account the respective flowconditions at the blades as a function of the azimuth angle. Inparticular, this therefore takes into account leeward flow effectscaused by the rotor and blades themselves such as turbulence and wakes,making it possible to further improve the energy yield of a verticalwind turbine according to the invention.

According to another embodiment, for wind speeds in the range of anominal wind speed, at an azimuth angle of 0° measured from a zero lineoriented perpendicularly to the wind direction, the pitch angle is lessthan zero. In other words, the blade is thus rotated into the wind witha pitch angle of less than 0° or more precisely stated, changes fromleeward to windward. This contributes to improved dynamics of a verticalwind turbine according to the invention and thus to an increased energyyield.

According to another embodiment, at least for wind speeds in thevicinity of the nominal wind speed, with azimuth angles of 0° to 90°measured from a zero line oriented perpendicularly to the winddirection, there is a local maximum of the pitch angle. This helps tooptimize the lifting forces acting on the respective blade. Thereby, thedynamics and energy yield of a wind turbine according to the inventionare further improved.

According to another embodiment, the vertical wind turbine has at leastone wind speed sensor and/or at least one wind direction sensor, whichis positioned on at least one of the blades and is connected in asignal-transmitting manner to a control device for determining asetpoint of the pitch angle. As a result, wind speed and/or winddirection as relevant measurement variables can be advantageouslydetermined at the blade and can be determined as close as possible to aclosed loop control system for adjusting the pitch angle, which systemincludes the blade and for example a pitch drive mounted on it orpositioned in the vicinity thereof. This promotes a pitch control thatis as precise and error-free as possible.

According to another embodiment, at wind speeds from still air up to afurther cut-off speed of the vertical wind turbine, an amount of apositioning error in the control of the pitch angle is essentiallyalways less than 5°, preferably less than 3°, most preferably less than1.5°. By means of such low positioning errors it is possible on the onehand to increase the energy yield of a vertical wind turbine accordingto the invention. On the other hand, this also makes it possible tominimize undesirable incorrect loading as well as vibrations and thelike of the vertical wind turbine because largely without deviation, therotation of the blades corresponds to a predetermined set-point value orset-point pitch angle.

According to another embodiment, a vertical wind turbine according tothe invention is provided in the form of a kit. As has already beenmentioned above, such a kit, which essentially includes all of thecomponents and parts of the vertical wind turbine and tools for theinstallation thereof, such as cranes, winches, and the like, makes itpossible to install a vertical wind turbine according to the inventionin sites that are not accessible or hardly accessible for horizontalwind turbines. A preparation of a vertical wind turbine according to theinvention in the form of a kit also helps to ensure that all of thecomponents, parts, and tools that are required for the installation,operation, and maintenance of the vertical wind turbine stem fromverified supply sources and satisfy desired safety and qualityrequirements.

According to another embodiment, a method according to the invention foroperating a vertical wind turbine can be improved by predetermining theangular positions by means of pitch cam disks. Thereby, set-point valuesfor adjusting the angular position are provided for essentially everyazimuth angle. Different pitch cam disks can be provided for differentwind speeds.

According to another embodiment of a method according to the invention,a wind speed, wind direction, and rotor rotation of a vertical windturbine rotor comprising the blades are included in the continuouscontrol. It is thus possible for a vertical wind turbine according tothe invention to be operated with the smallest possible set-pointdeviations of the angular positions and thus in an extremely efficientway.

Further, the disadvantages from the prior art can be overcome by meansof a vertical wind turbine according to the invention with a pluralityof vertical blades, which are each fastened to a respective verticalblade axis such that they are pivotable in a motor-driven mannerindependently of one another around a respective blade rotation axis,and are supported rotatable on a common circular path around a verticalrotor rotation axis, wherein the blade axes are each being provided withat least one pitch motor for motor-driven pivoting of the blades, amotor shaft of which extends concentrically to the respective bladerotation axis.

With a method according to the invention, the disadvantages of the priorart are further overcome in that angular positions are predetermined forvertical blades of the vertical wind turbine that are driven around arespective vertical blade axis, wherein the angular positions arecontinuously controlled by means of a direct drive of the blades througha respective pitch motor positioned concentrically to the blade axis.

This has the advantage that it enables a very precise and energy-savingdriving of the blades in accordance with pitch cam disks. The angularpositions of the blades can be optimally set without delay and takinginto consideration the varying system conditions (wind speed, winddirection, rotor rotation, power output, etc.) at a power consumption ofthe pitch motors of at most less than 10% to preferably less than 0.5%,for example 0.3%, of a generator output power of the vertical windturbine.

According to a further embodiment of a vertical wind turbine accordingto the invention, the pitch motor is embodied as a torque motor with atleast one rotor that is torsionally rigidly coupled to the blade axis.For example, the torque motor can be embodied as a permanently excitedbrushless DC motor with an internal-rotor design. The rotor, which isthus surrounded along its outer circumference by a stator of the pitchmotor, can be torsionally rigidly coupled in a simple and effective wayto a motor shaft of the pitch motor with the aid of a clamping set.

According to another embodiment, the blade axes are supported on motorbearings in the pitch motor. In other words, the blades can be securedin a rotatable manner in the pitch motor. For example, the bearing canbe implemented by means of tapered roller bearings, rolling bearings, orconical roller bearings, which are positioned in an axially prestressedfashion between the blade axis and motor on the one side and the statoron the other in order to absorb both axial forces and radial forces.This enables a precise positioning of the blade axes with a long servicelife and a highly efficient driving of the blade axes by means of thepitch motor with low friction losses.

According to another embodiment, the motor bearings are positioned in abearing receiving chamber that is sealed up against the surroundings ofthe vertical wind turbine with the aid of sealing elements. The bearingreceiving chamber can contain lubricant such as grease for lubricatingthe motor bearings. Preferably, the bearing receptacle is filled withthe lubricant, which is replaced or refilled, respectively, every 5years, depending on the requirements. Thereby, an effective lubricationof the motor bearings is achieved, which helps to further maximize theservice life of a vertical wind turbine according to the invention.

The bearing receiving chamber can in turn be sealed relative to a motorinterior with the aid of additional sealing elements such that the motorinterior is protected from harmful environmental influences in anessentially hermetically sealed way. The motor interior can be at leastpartially formed by a motor housing and/or enclosed by it.

An expansion or compensation vessel can be connected to the hermeticallysealed motor interior in a fluid-conducting way via at least one fluidline and can constitute a changeable expansion or compensation volume inorder to compensate for temperature-induced volume changes of fluids, inparticular air, contained in open spaces inside the motor chamber. Toavoid the presence of open spaces in the motor interior, space-fillingelements can be positioned in the motor chamber, which can be formed offoam material, for example. The expansion vessel and space-fillingelements on the one hand help to prevent humidity from condensing in themotor interior. On the other hand, expansion vessel and space-fillingelements prevent bearing lubricant and/or motor lubricant such as greasefrom being displaced or escaping when pressure fluctuations occur.

According to another embodiment, the blades can be supported rotatablearound their blade rotation axis at at least one additional bearingpoint arranged at a distance from the pitch motor. In this way, thepitch motor can, for example, be positioned between two additionalbearing points. There are thus two respective blade sections per blade,namely a blade section between the upper bearing point and the pitchmotor and a blade section between the pitch motor and the lower bearingpoint.

Preferably, a bearing unit is positioned at each of the outer ends ofthe blade pointing away from the pitch motor. The bearing unit includesa housing, two roller bearings, and a hollow shaft that connects therotor blades of the blades to one another. At the additional bearingpoints, spherical roller bearings can be used, which absorb high radialforces occurring mainly at the blade ends and help to stiffen the rotorsystem as a whole. By contrast, the motor bearings can include, forexample, two axially prestressed conical roller bearings that absorb theentire weight force of the blades.

According to another embodiment, the blade axes can each include a vaneaxis section in the region of a vane of the blade and a transitionsection positioned between the vane axis section and the motor shaft.The transition section and motor shaft can, for example, be integrallyformed of a single piece of metal. The transition section allows for anoptimal connection between the motor shaft and the vane axis section.

According to another embodiment, the transition section tapers in adirection extending away from the motor shaft. For example, thetransition section can be shaped in the form of a stud. An outerdiameter of the motor shaft can be greater than an inner diameter of thevane axis section. The transition section thus helps to overcomedimensional differences between the motor shaft and the vane axissection and to connect them to each other in a precisely fitting way.

According to another embodiment, the pitch motors each have a motorhousing at which a blade mount is mounted that connects the blades to arotor hub of the vertical wind turbine. The blade mount can, forexample, include a plurality of struts. At least one of these struts canbe directly connected to the pitch motor in order to secure therespective blade.

According to another embodiment, the blade mount includes a plurality ofstruts, with at least one respective strut being flange-mounted to themotor housing. On the outside of the motor housing in the region of anouter circumference of the stator, each strut can be advantageouslyflange-mounted onto the end of the pitch motor. This permits aweight-reducing, highly stable design of the rotor as a whole since thepitch motor simultaneously functions as a driving point, bearing point,and connecting point between the blade mount and the blade.

According to another embodiment, the motor housing includes supportribs, which extend radially to the motor shaft and connect a bearingseat of the pitch motor on the side of an outer circumference of thebearing seat to a wall of the pitch motor housing facing in axialdirection. Such support ribs help to reliably transmit forces that themotor shaft introduces onto the motor housing via the bearing points toa connection point of the blade mount on the motor housing, for examplethe above-mentioned motor flange. The rigidity of the motor housing isincreased while its weight is kept as low as possible.

According to another embodiment, the pitch motor is cased-in with acasing that is formed in accordance with aerodynamic aspects. The casingcan minimize an aerodynamic drag caused by the pitch motor, which helpsto further increase the efficiency of a vertical wind turbine accordingto the invention. In addition, the casing helps to minimize anyintermediate spaces between the blade sections and between the bladesections and the motor and thus to prevent a pressure compensation atthe intermediate spaces. In a similar way, casings or covers can also beprovided in the region of the additional bearing points or bearing unitsbetween the blade sections in order to counteract pressure compensationand the efficiency loss that this entails.

According to another embodiment, the vertical wind turbine has a controldevice for control of the pitch motors, that is connected in asignal-transmitting manner to the pitch motors and to at least one windspeed sensor and/or at least one wind direction sensor. The controldevice calculates a set-point angle of the blades for each pitch motor,for example cyclically, and transmits it via a communication device to acontrol section of an inverter system, which in addition to the controlsection, also has a supply section for each pitch motor. The controlsection provides a position control of the blades in order to set adesired angular position in accordance with the set-point angle. To thatend, the power section continuously inverts an electric current of forexample 150 A_(RSM) and briefly outputs a peak current of 210 A_(RMS) inorder to achieve a maximum torque of the pitch motors. The controldevice in this case monitors a precision of the blade adjustment and astate of the drive control and is able to influence them.

According to another embodiment, the at least one wind speed sensorand/or the at least one wind direction sensor is arranged in the regionof at least one of the pitch motors. For example, the at least one windspeed sensor and/or the at least one wind direction sensor can bemounted on a rod, which is fastened to the pitch motor or in the regionof the pitch motor and protrudes beyond an outer edge of the blade. Inparticular, the at least one wind speed sensor and/or the at least onewind direction sensor can be mounted on a distal end of the rod orientedaway from the blade. As a result, the at least one wind speed sensorand/or the at least one wind direction sensor is preferably situatedoutside of an influence region of the blade in which air flow changesand turbulence caused by the blade could occur. Alternatively, oradditionally, sensors such as a wind speed sensor and/or wind directionsensor as well as other signaling and measuring means can be positionedon a mast positioned centrally on the rotor hub and preferablyprotruding in the vertical direction beyond an upper end of the blades.

DESCRIPTION OF FIGURES

Exemplary embodiments of the invention will be described below based onthe following figures. In the drawings:

FIG. 1 shows a schematic perspective view of a vertical wind turbineaccording to the invention;

FIG. 2 shows a schematic side view of a vertical wind turbine accordingto the invention;

FIG. 3 shows a schematic top view of a vertical wind turbine accordingto the invention;

FIG. 4 shows a detail IV indicated in FIG. 2 of a blade of a verticalwind turbine according to the invention;

FIG. 5 shows a detail V indicated in FIG. 4 of a blade of a verticalwind turbine according to the invention with a pitch motor according tothe invention in a schematic cross-sectional view along a rotation axisof the blade;

FIG. 6 shows a schematic perspective view of an aerodynamically coveredpitch motor of a vertical wind turbine according to the invention;

FIG. 7 shows a schematic cross-sectional view of a drive train of avertical wind turbine according to the invention along a drive shaft ofthe drive train;

FIG. 8 shows a schematic perspective view of a first embodimentaccording to the invention of a hub connection of a vertical windturbine according to the invention;

FIG. 9 shows a perspective view of another embodiment according to theinvention of a hub connection of a proper vertical wind turbine;

FIG. 10 shows a schematic top view of a vertical wind turbine accordingto the invention during operation to illustrate angular positions andforce conditions at blades of the vertical wind turbine;

FIG. 11 shows a schematic diagram to illustrate the function of acontrol device according to the invention belonging to a vertical windturbine according to the invention;

FIG. 12 shows a schematic diagram with a sample torque characteristiccurve of a pitch motor according to the invention for a vertical windturbine according to the invention;

FIG. 13 shows a schematic diagram with sample cam disks for controllinga pitch motor for a vertical wind turbine according to the invention;

FIG. 14 shows a schematic perspective view of a test bench fordetermining a positioning error of a pitch motor of a vertical windturbine according to the invention;

FIG. 15 shows a schematic diagram of a positioning error of a pitchmotor according to the invention, which has been determined by means ofthe test bench shown in FIG. 14, over a plurality of control cycles;

FIG. 16 shows a schematic diagram of a positioning error of a pitchmotor according to the invention over one control cycle at a; and

FIG. 17 shows a schematic diagram of a positioning error of a pitchmotor according to the invention over one control cycle at a cut-outwind speed.

IMPLEMENTATION OF THE INVENTION

For better comprehension of the present invention, reference is made tothe drawings in the following. The drawings merely show exemplaryembodiments of the subject-matter of the invention; as described above,features can be arbitrarily combined with one another or also omitted,depending on the respective requirements.

FIG. 1 shows a schematic perspective view of a vertical wind turbineaccording to the invention 1. The vertical wind turbine 1 extends alonga longitudinal direction X, a transverse direction Y, and a verticaldirection Z, which together define a Cartesian coordinate system. Thevertical wind turbine 1 includes a rotor 2, a nacelle 3, a tower system4, footings 5, and a container-like switchgear box 6.

The rotor 2 includes a plurality of vertical blades 7, which arefastened by means of a blade mount 8 to a rotor hub 9, which issupported in the nacelle 3 so that it is able to rotate around a rotorrotation axis C₂ that is vertically oriented, i.e. extends parallel tothe vertical direction Z. The blade mount 8 includes rotor arms 10,which extend between the blades 7 and the rotor hub 9. A signalingand/or measuring mast 11 is positioned on the rotor hub 9 concentric tothe rotor rotation axis C₂.

As a rule, the nacelle 3 is positioned at the top of the tower system 4,is cased-in in a sound-absorbing way, and contains a drive train of thevertical wind turbine 1 (generator, rotor bearing system, transmission,mechanical brake, and cooling/lubricating system, see FIG. 7). The towersystem 4 is preferably embodied as a lattice mast tower. The footings 5are preferably concrete footings, which absorb the load of the towersystem 4, the nacelle 3, and the rotor 2. Other components such aselectrical transformers, switch components, and a control device (seeFIG. 11) of the vertical wind turbine 1 are preferably accommodated inthe switchgear box 6.

The blades 7 are supported so that they are able to rotate around ablade rotation axis C₇, which likewise extends essentially parallel tothe vertical direction Z. For the rotation of each of the blades 7around its respective blade rotation axis C₇, they are each providedwith at least one pitch drive 12. At least one of the rotor arms 10 isconnected to the pitch drive 12, which can thus help absorb a load ofthe blade 7.

FIG. 2 shows a schematic front view of the vertical wind turbine 1.Here, it becomes clear that the blades 7 have a plurality of bladesections 13, namely an upper end section 13 a, an upper middle section13 b, a lower middle section 13 c, and a lower end section 13 d. Thepitch drive 12 is positioned between the upper middle section 13 b andlower middle section 13 c. Between the upper end section 13 a and themiddle end section 13 b as well as between the lower middle section 13 cand the lower end section 13 d, an additional bearing point 14 isprovided, respectively.

At the bearing points 14 between the upper end section 13 a and uppermiddle section 13 b and between the lower middle section 13 c and thelower end section 13 d, the blades 7 are each connected by means of oneof the arms 10 to the rotor hub 9, which is designed only to transmitforces acting radially relative to the rotor rotation axis C₂, saidforces therefore acting essentially in a horizontal plane, which isdefined parallel to the longitudinal direction X and transversedirection Y. Since the lower ones of the arms 10 are positioned in theregion of the lower middle section 13 c and in the region of the lowerend section 13 d in the vertical direction Z below the nacelle 3 at thelevel of the tower system, the arms 10 are connected to the rotor hub 9there by means of a transverse mount 15. The transverse mount 15includes a plurality of transverse struts 16, which, between the arms 10and a transverse connecting element 10 a, are connected to the arms 10and a transverse connecting element 10 a and secure them.

At the pitch drive 12, between the upper middle section 13 b and lowermiddle section 13 c of the blades 7, forces are absorbed, which act bothradially and in parallel to the rotor rotation axis C₂. Consequently,the entire weight load of the rotor 2 is absorbed at the pitch drive 12.In addition to the arms 10 horizontally connecting the pitch drive 12 tothe rotor hub 9, a support structure 17 is configured to absorb theweight load of the rotor 2. The support structure 17 includes transversestruts 15 that support the arms 10, which are mounted to the pitch drive12, by transferring loads beneath the arms 10 to the rotor hub 9 at alower end section thereof.

Further, it is illustrated in FIG. 2 that the rotor hub 9 and the towersystem 4 are each embodied as a tubular lattice structure. At the top ofthe tower system 4 embodied as a lattice mast tower, it tapers in thedirection toward the nacelle 3 and at this location, absorbs all of thestatic and dynamic loads generated by the rotor 2. At the bottom of thetower system 4, the loads are transferred to the ground by means of thefootings 5. The nacelle 3 can be accessed by means of a ladder, notshown, which will not be discussed in detail.

A maximum width B₄ of the tower system 4 measured parallel to thelongitudinal direction X at the footings 5 is 22 m, for example. Alength L₇ of the blades 7 measured parallel to the vertical direction Zis 54 m, for example. An overall height of the vertical wind turbine 1measured to include a height of the footings extending above the groundis 105 m without the signaling and/or measuring mast 11, for example,and 110 m including the signaling and/or measuring mast 11.

FIG. 3 shows a schematic top view of the vertical wind turbine 1. Here,it becomes clear that the blades 7 have a blade profile and move on acircular path K around the rotor rotation axis C₂. A diameter D_(K) ofthe circular path K is 32 m, for example, and approximately correspondsto a maximum diameter of the tower system 4.

At their proximal ends, the arms 10 have two struts 18, ends of whichare spaced horizontally apart from each other and are connected to therotor hub 9. At their distal ends, the arms 10 are combined to form asingle strut 18. At a connecting point 19, the struts 18 leading to theproximal end are merged in fork-like fashion with the strut 18 leadingto the distal end, to which the pitch drive 12 is fastened. In addition,the transverse connecting element 10 a of the transverse mount 15 iscomposed of three struts 18 that are connected to one another at theirends, which define an equilateral triangle in a projection along thevertical direction Z, which lies in a plane extending parallel to thelongitudinal direction X and transverse direction Y.

FIG. 4 a detail IV indicated in FIG. 2 of one of the blades 7 of thevertical wind turbine 1. The blade 7 has vanes 19, which are eachfastened to an arbor 20 and is positioned concentric to the bladerotation axis C₇. Between the upper end section 13 a and the uppermiddle section 13 b and between the lower middle section 13 c and thelower end section 13 d, the blade 7 is respectively supported in abearing unit 21 so that it is able to move in rotation around the bladeaxis C₇. The bearing unit 21 includes a bearing housing 22 in which tworolling bearings 23 are positioned, which enclose a bearing shaft 24 ofthe bearing unit 21, which shaft is embodied as a hollow shaft.

Between the upper middle section 13 b and lower middle section 13 c, theblade 7 is supported in the pitch drive 12 on a motor shaft 25 of thepitch drive 12. Together with the bearing shafts 24 and the motor shaft25, the arbors 20 form a blade axis 26, which passes through the entirelength of the blade 7 and to which the vanes 19 are firmly connected andsupported such that they are held pivotably movable in rotating fashion.For example, the vanes 19 can be produced with a shell construction andbe fastened to the arbor 20. To this end, the vanes 19 have an outerskin for absorbing torsional forces, an arbor flange for absorbingbending moments, an arbor strut, as well as ribs and stringers forpreventing undulations or bulges in the outer skin (see FIG. 5).

FIG. 5 shows a detail V indicated in FIG. 4 of the blade 7 with thepitch drive 12 in a schematic cross-sectional view along the bladerotation axis C₇. The pitch drive 12 has a pitch motor 27, which ispositioned in a clearance 28 between the upper middle section 13 b andlower middle section 13 c of the blade 7. The pitch motor 27 is embodiedas an electronically controlled, transmissionless, air-cooled torquemotor and has a stator ring 29 and a rotor ring 30 that iscircumferentially surrounded by the stator ring 29 and is spaced apartfrom it by a gap. A cooling body 31 with cooling fins 32 is fastened toan outer circumference surface of the stator ring 29 so as to be able todissipate waste heat of the pitch motor 27.

The rotor ring 30 of the pitch motor 27 is mounted on two disk-shapedrims 33, which connect the rotor ring 30 in a rotationally coupledfashion to the essentially cylindrical motor shaft 25 by means of aclamping set 34. By means of the clamping set 34, a drive torque of thepitch motor 27—which is electromagnetically generated between the statorring 29 and the rotor ring 30 and acts in a direction oriented aroundthe blade rotation axis C₇—is transferred from the rotor ring 30 to themotor shaft 25.

A motor housing 35 of the pitch motor 27 forms a motor interior 36 inwhich the rotor ring 30 is accommodated. The motor housing 35 has a top37 and a bottom 38, which extend in a disk shape along and essentiallyparallel to the rim 33. On their inner circumference sides, the top 37and bottom 38 are each respectively connected to a bearing seat 39. Onthe outer circumference side, the top 37 and bottom 38 are connected tothe stator ring 29 and cooling body 31 and, on a side of the pitch motor27 facing the strut 18 that supports the blade 7, are connected to amotor flange 40 of the pitch drive 12.

The motor flange 40 provides end surfaces 41 at which the strut 18 isconnected to the motor flange 40 by means of a mounting flange 42connected to the rotor arm 10. The mounting flange 42 provides acounterpart end surface 43 that faces radially away from the rotorrotation axis C₂ in the direction toward the circular path K of theblades 7. The motor flange 40 and mounting flange 42 are connected toeach other by means of connecting elements 44, which are embodied forexample in the form of detachable connecting elements 44 such as boltedconnections. Between the end surfaces 41 of the motor flange 40, thereis an open space 40 a in order to provide sufficient space in the regionof the cooling fins 32 for heat dissipation or more precisely stated, toprevent a heat buildup.

Reinforcing ribs 45 extend between the bearing seat 39 and motor flange40 in order to be able to transmit the static and dynamic loads, whichoriginate from the blade 7, from the bearing seat 39 via the motorhousing 35 to the motor flange 40 with as little distortion of the motorhousing 35 as possible. In the remaining sections of the motor housing35, support ribs 46 are provided, which extend radially outward from theannular bearing seat 39 along the cover 37 and bottom 38 in order tostiffen them and to prevent distortions of the motor housing 35.

Reinforcing ribs 45 and support ribs 46 are each advantageouslyintegrally joined, for example by means of welding, to the top 37,bottom 38, bearing seat 39, and motor flange 40 or to the top 37, bottom38, and bearing seat 39; they extend into and away from the upwarddirection Z and away from the top 37 and bottom 38 in strut-likefashion. In addition to their reinforcing action, the reinforcing ribs45 and support ribs 46 also contribute to the cooling of the pitch motor37 through heat dissipation via the motor housing 35.

Respective motor bearings 47 are positioned between the two bearingseats 39 and the motor shaft 25. For example, the motor bearings 47 areembodied in the form of spherical roller bearings. They transmit highradial forces from the blades 7 to the struts 18 of the rotor arms 10and also stiffen the rotor 2 as a whole. In order to protect the motorbearings 47 from harmful environmental influences, the motor bearings 47are each accommodated in a bearing receiving chamber 48, which, to thegreatest extent possible, is hermetically sealed by means of sealingelements 49.

The sealing elements 49 seal the bearing receiving chamber 48, both inrelation to the motor interior 36 and in relation to the surroundings ofthe vertical wind turbine 1. Toward the motor interior 36, the bearingreceiving chamber 48 is sealed by means of inner rings 50, which—restingagainst the motor bearing 47 and, on the outer circumference side,against the sealing element 49 in the axial direction of the blade 7,both in and away from the upward direction Z, respectively—isolate thebearing receiving chamber 48 from the motor interior 36. The bearingreceiving chamber 48 is sealed in relation to the surroundings of thevertical wind turbine 1 by means of outer rings 41, which respectivelyrest against the outside of the bearing seat 39 and enclose the sealingelement 49 on the inner circumference.

At its ends oriented toward the vanes 19, the motor shaft 25 isconnected to a transition section 52 or transitions into it in integralfashion. The transition section 52 tapers as it extends away from thepitch drive 12 and is accommodated in a vane axis section 53, whichrotationally couples the transition section 52 to ribs 54 of the blade 7in adapter fashion, which ribs extent transversely to the blade rotationaxis C₇. To that end, connecting ends 55 of the transition section 52extending in the direction along the blade rotation axis C₇ areaccommodated in fixing elements 56, which enclose the connecting ends 55at least in a by force-fit and have flange sections 57 oriented radiallyaway from the connecting ends 55, on which positive-fit elements 58 andother connecting elements 59 are provided, for example likewisedetachable ones in the form of bolt connections, which create apositive-fit and/or force-fit engagement the fixing elements 56 and therespective rib 54.

The motor shaft 25, transition section 52, vane axis section 53, andarbor 20 extend coaxially to one another. In this case, the arbor 20encompasses the vane axis section 53, which in turn encompasses thetransition section 52. The ribs 54 are rotationally coupled to the arbor20 and support an outer skin 60 of the blade 7.

FIG. 6 shows a schematic perspective view of the pitch drive 12 in whichthe pitch motor 27 is provided with an aerodynamic cover in the form ofa casing 61. The casing 61 has a upper shell 62 and a lower shell 63,which enclose the pitch motor 27 in the vicinity of the top 37 andbottom 38 like a cowling and thus cover the top 37 and bottom 38together with the reinforcement 45 and support ribs 46, thus minimizingthe size of a drive gap 64 that is formed between the pitch drive 12 andthe blade 7 and minimizing the accompanying losses in pressure andoutput that occur at such a gap. Between the upper shell 62 and lowershell 63, an annular gap-shaped cooling opening 65 is formed, whichaxially surrounds the cooling body 31 and through which the cooling fins32 freely extend so that with ambient air circulating unhindered aroundthem, they can give off the waste heat of the pitch motor 27 to thesurroundings of the vertical wind turbine 1.

The drive gap 64 is further reduced in that the casing 61 provides anextension 66, which is formed in accordance with aerodynamic aspects,which adjoins the upper shell 62 and lower shell 63, and an outercontour of which in a projection along the blade rotation axis C₇essentially corresponds to a blade profile of the blades 7. In thedirection toward the rotor arm 10, the casing 61 is provided with endcaps 67, which rest flush against the motor flange 40 and an outerdiameter of which, at least in some places, is adapted to an outerdiameter of the mounting flange 42. An outer contour of the mountingflange 42 is in turn adapted to an outer contour of the strut 18. As aresult, the end caps 67, the motor flange 40, the connecting flange 42,and the strut 18 transition into one another with outer contours thatare as flush with one another as possible and there is anaerodynamically advantageous transition between the pitch drive 12 andthe blade mount 8.

FIG. 7 shows a schematic cross-sectional view of a drive train 70 of thevertical wind turbine 1 along a drive shaft 71 of the drive train 70, adrive rotation axis C₇₁ of which extends coaxial to the rotor rotationaxis C₂. The rotor hub 9 has a pedestal 72 that forms a stud 73, whichlikewise extends coaxial to the drive rotation axis C₇₁ and rotorrotation axis C₂. At the place where the pedestal 72 tapers toward thestud 73, a hub shoulder 74, which points away from the upward directionZ, is formed on the pedestal 72 and rests on a transition ring 75, whichin turn rests axially in a direction oriented away from the upwarddirection Z on a first rotor bearing 76 a, which constitutes a part of arotor bearing system 76.

In addition to the first rotor bearing 76 a, the rotor bearing system 76also includes a second rotor bearing 76 b and a third rotor bearing 76c. The first and second rotor bearings 76 a, 76 b are embodied forexample as prestressed conical roller bearings and transmit radial loadsresulting from wind loads to the tower system 4. For this purpose, thefirst and second rotor bearings 76 a, 76 b are mounted on a rotor shaft78 by means of a separate bearing bush 77. The part of the rotor bearingsystem 76 comprising the first and second rotor bearings 76 a, 76 b isassembled in an axially free-floating fashion in a hub connection 79that constitutes a machine support and therefore remains free ofvertical loads. The third rotor bearing 76 c absorbs the vertical loadsof the rotor 2 and thus essentially its weight force and for thispurpose, is advantageously embodied in the form of an axial sphericalroller bearing, which introduces the vertical loads directly into thenacelle 3.

Below the nacelle 3, a transmission 81 of the vertical wind turbine 1 isarranged in which a rotor speed of the rotor shaft 78 is converted intoa generator rotation speed at an output shaft 82 of the transmission 81.A clutch unit 83, for example in the form of a double-Catalan,torsionally rigid steel disk clutch, connects the output shaft 82 in atorque-transmitting fashion to a generator shaft 84 of a generator 85,for example a synchronous machine with permanent magnets, in order toproduce electrical current, in this case for example with a maximumpower of 750 kW. The clutch unit 83 prevents a redundant dimensioning ofbearing forces. To limit the torque, the rotor shaft 78 is provided withan intended break point 86 (for example with a nominal torque of 500kNm; an intended break moment of 1000 kNm; and a permissibletransmission peak torque of 1500 kNm).

The transmission 81 converts the low rotor speed according to theinvention into a high generator rotation speed. For example, atransmission step-up factor i amounts to roughly 75. A transmissionhousing 87 of the transmission 81 is rigidly screw-mounted to the hubconnection by means of a flange bell 88. This results in a directfeedback of the high operating torque. Between the rotor shaft 78 anddrive train 70, there is a double-cardan, spherically grounddouble-tooth clutch 89, which transmits the torque of the rotor 2 to thetransmission 81 without redundant dimensioning of bearing forces.

In addition, a pitch pipe 90 passes through the transmission 81 coaxialto the rotor shaft 78 and serves as a feed-through for control wires andpower cables for the pitch drive 12. The pitch pipe 12 is driven to apoint above the intended break point 86 in the coupling 89 by beingrotationally coupled to the rotor 2. Thus, after a breakage occurs atthe intended break point 86 and after the system subsequently coasts toa stop, the cables and lines for transmitting signals and/or power (seeFIG. 11) are not twisted and therefore remain intact.

FIG. 8 shows a schematic perspective view of a first embodimentaccording to the invention of the hub connection 80 of the vertical windturbine 1. The hub connection 80 includes a cylindrical, drum-likeintegrally formed base body 91, which provides a feed-through 92 foraccommodating a shaft bearing unit 93 (see FIG. 7) of the drive train70. Supporting feet 94 are fastened equidistantly to the outercircumference side of the base body 91 and extend out radially from it.The supporting feet 94 each provide a horizontally oriented rest 95 formounting the hub connection 80 onto the tower system 4. The supportingfeet 94 can for example be composed of welded-together plates and beintegrally connected to the base body 91 by welding or be flange-mountedto it; the base body can in turn also be composed of welded-togetherplates.

FIG. 9 shows a schematic perspective view of a second embodiment of ahub connection 80′. By contrast with the embodiment of the hubconnection 80 shown in FIG. 8, the hub connection 80′ is composed of aplurality of identically shaped segments 96, which each provide twoflange ends 97, at which they are connected to one another enclosing acircle and thus combine to form a feed-through 92′ for accommodating theshaft bearing unit 93. Each of the segments 96 constitutes a supportingarm 98. At the distal end of each supporting arm 98 oriented away fromthe feed-through 92′, a vertically extending supporting tab 99 isformed, which lies in a respective radial plane relative thereto forbeing mounted onto the tower system 4. For example, the segments 96 canbe cast individually, which can help to reduce manufacturing costs,particularly in mass production and can help to adapt materialthicknesses of the segments 96 in high-stress points and can also helpto provide rounded regions on it in order to reduce stressconcentrations, for example by having the flange ends 97 transition intothe supporting arms 98 by forming a curved profile.

FIG. 10 shows a schematic top view of the vertical wind turbine 1 toillustrate angular positions and force conditions at the blades 7 duringthe operation of the vertical wind turbine 1. During the operation ofthe vertical wind turbine 1, the wind flows against the blades 7 at awind speed v_(W). The rotation of the rotor 2 around the rotor rotationaxis C₂ produces an angular velocity ω of the rotor 2, which, multipliedby a radius R_(K) of the circular path K that corresponds to half of thediameter D_(K) of the circular path K, yields a circumferential speedv_(U) of the blades 7 along the circular path K according to equation(1) below:

v _(U) =ω×R _(K)  (1)

A difference between the wind speed v_(W) and the circumferential speedv_(U) yields a relative speed v_(R) of the blade 7 moving along thecircular path K in relation to the wind according to equation (2) below:

v _(R) =v _(W) −v _(U)  (2)

Between the vectors of the circumferential speed v_(U) and the relativespeed v_(R) at the blade 7, there is an angle of incidence γ, which iscalculated according to equation (3) below from a sum of a relativeangle of incidence or angle of attack α and a gradient angle or pitchangle β:

γ=α+β  (3)

The angle of attack α is respectively measured between the vector of thecircumferential speed v_(U) and a chord line 100 of the blades 7, whichextends in a straight line between a leading edge 101 and a trailingedge 102. The pitch angle β is measured between the vector of therelative speed v_(R) and the chord line 100. The blades 7 have asymmetrical blade profile, by means of which the blade chord forms aplane of symmetry of the blades 7 or their vanes.

Through the rotation of the rotor 2 around the rotor rotation axis C₂,the relative speed v_(R) is a function of an azimuth angle θ of therotor 2, which is measured for example for the respective rotor arm 10starting from a zero point at a position 90° from the wind direction,facing into the wind and rotating relative to a main axis of thevertical wind turbine 1. A tangent of the angle of incidence γ iscalculated as a function of the wind speed v_(W), the relative speedv_(R), and the azimuth angle θ or as a function of a tip speed ratio λand the azimuth angle θ according to equation (4) below:

$\begin{matrix}{{{\tan \mspace{14mu} \gamma} = {\frac{v_{W}\mspace{14mu} \sin \mspace{14mu} \theta}{v_{R} + {v_{W}\mspace{11mu} \cos \mspace{14mu} \theta}} = \frac{\sin \mspace{14mu} \theta}{\lambda \mspace{14mu} \cos \mspace{14mu} \theta}}},} & (4)\end{matrix}$

where the tip speed ratio λ in turn, according to equation (5) below,corresponds to a ratio of the circumferential speed v_(U) to the windspeed v_(W) and according to the invention, is to be set as optimally aspossible and kept constant by means of the respective pitch drive 12 ormore precisely, its pitch motor 27, in accordance with the respectivewind conditions with varying pitch angles β in order to maximize anenergy yield or performance of a vertical wind turbine 1 according tothe invention:

$\begin{matrix}{\lambda = \frac{v_{U}}{v_{W}}} & (5)\end{matrix}$

In order to minimize an adjusting torque of the pitch drive 12—which isrequired to vary the pitch angle β by rotating the blade 7 around therotor rotation axis C₇—, it is advantageous if a static center ofgravity of the blade 7 lies on or as close as possible to the rotorrotation axis C₇. For example, the rotor rotation axis C₇ is positionedon the chord line 100 at 20 to 23%, preferably 21.5%, of a rotor bladedepth measured from the leading edge 101. In order to position thecenter of gravity on the rotor rotation axis C₇, a counterweight 103 ispositioned in the region of the leading edge 101 in the blade 7. Forexample, the counterweight 103 is composed of rod segments, preferablyof a round steel rod with diameters of between 60 and 100 mm, mostpreferably 80 mm. The rod segments are fastened to the ribs 54. Thesegments can be advantageously connected to one another in anelectrically conductive fashion. As a result, the counterweight 103 canperform a double function in that it also serves as a lightning rod.

In addition, the vertical wind turbine 1 has at least one wind speedsensor 104 and/or wind direction sensor 105. The wind speed sensor 104and/or wind direction sensor 105 is positioned at the upper end of thesignaling and/or measuring mast 11 and/or on at least one of the blades7 or on all of the blades 7. The wind speed sensor 104 and/or winddirection sensor 105 is preferably fastened to the blade 7 in the regionof the pitch drive 12 because wind speeds and/or directions measuredthere are highly relevant for the control of the pitch drive 12.

In order to keep the wind speed sensor 104 and/or wind direction sensor105 outside of air turbulence caused by the blade 7, the wind speedsensor 104 and/or wind direction sensor 105 is positioned at the distalend of a rod 106, which is fastened to the blade 7 or pitch drive 12and, oriented radially away from the rotor rotation axis C₂, protrudesbeyond the circular path K into a region in the vicinity of the verticalwind turbine 1, which lies as far as possible outside of air flowboundary layers that are formed around the rotor 2 and its components,i.e. largely outside of the influence range of the blade 7.

FIG. 11 shows a schematic diagram to illustrate the function of acontrol device according to the invention 107 of the vertical windturbine 1. The control device 107 includes a supply unit 108, which ison the one hand connected to a motor control unit 109 that includes apower section 110 and on the other hand, is connected to a choke 111 anda filter 112 in order to ensure the most malfunction-free and error-freepower supply possible. For example, the power unit 110 is embodied as aninverter.

Via lines 113 for transmitting signals and/or power, the motor controlunit 109 is connected to the pitch drive 12, a power supply unit 114,and a control unit 115 for monitoring and controlling the vertical windturbine 1. The power supply unit 114 includes a main power supply unit116 and an auxiliary power supply unit 117, the latter ensuring anemergency power supply to the control device 107 if the main powersupply unit 116 fails or is not available.

In addition, the control device 107 includes a motor protection unit 118and a data transmission unit 119. The pitch drive 12 also includes arotary position transducer 120 with a position sensor 121 for monitoringa rotation position of the rotor ring 30 relative to the stator ring 29.The pitch motor 27 also includes a motor unit 122, which includes atleast the stator ring 29 and the rotor ring 30, and a temperaturemeasuring unit 123, which has a first temperature sensor 124 and atleast one other temperature sensor 125. For example, the firsttemperature sensor 124 is embodied as a resistance-dependent temperaturesensor (KTY), whereas the other temperature sensor 125 is embodied forexample as a temperature sensor with a positive temperature coefficient(PTC).

During operation of the vertical wind turbine 1, the power section 110of the motor control unit 109 of the control device 107 inverts—forexample continuously—a current that is required to drive the pitch motor27. For example, the power element 110 can output a continuous currentof 100 to 200, preferably 150 A_(RMS), and produce a peak current of 200to 250, preferably 210 A_(RMS), so that it is possible to quickly obtaina maximum torque of the pitch motor 27. The control unit 115 cyclicallycalculates a set-point value S for the adjustment of each of the blades7, for example in the form of a set-point pitch angle β_(S), andsupplies it via the corresponding line 113 to the motor control unit109.

With the aid of the rotary position transducer 120, an actual value Isuch as an actual pitch angle β_(I) is determined and is transmitted viathe corresponding line 113 to the motor control unit 109. Based on theset-point value S and the actual value I, the motor control unit 109determines a differential value d, for example an angular deviation δ,and based on it, derives a control value U, for example in the form of acontrol current A, which is transmitted to the respective drive unit 12and/or the motor unit 122 of the pitch motor 27. Correspondingly, themotor control unit 109 adjusts the pitch angle β according to theinvention with the least possible angular deviation δ.

With the aid of the temperature sensor 124 and the other temperaturesensor 125, the temperature measuring unit 123 detects a firsttemperature measurement value T and at least one other temperaturemeasurement value T_(x), which are determined for redundancy reasonsand/or for different uses. Thus, the temperature measurement value T istransmitted via one of the lines 113 to the motor protection unit 118.The motor protection unit 118 compares the temperature measurement valueT to a temperature limit value and if the temperature limit value isexceeded, can transmit an alarm signal via the corresponding line 113 tothe motor control unit 109, where preventive measures for protecting therespective pitch drive 12 are initiated, for example an emergencyshut-off or interruption of the power supply. At the same time, themotor protection unit 118 can use the corresponding line 113 to transmittemperature values for relaying temperature data to the motor controlunit 109 and/or control unit 115 and the data transmission unit 119.

The other temperature measurement value T_(x) is transmitted viacorresponding lines 113 directly to the motor control unit 109 in orderto keep a temperature of the drive unit 12 and the components thereofwithin the scope of a predetermined or specified operating temperature.In the motor control unit 109, immediate temperature control measurescan be initiated, whereas in the control unit 115, longer-termtemperature control measures can be carried out. Thus, with the aid ofthe alarm signal sent by the motor protection unit 118 on the basis ofthe temperature measurement value T, a rapid temperature control can becarried out in order to protect the drive unit 12, whereas thetemperature data that are related to the control unit 115 can be used toperform a long-term temperature control and through the direct relayingof the other temperature measurement value T_(x) to the motor controlunit 109, a middle-term temperature control is possible.

The control device 107 is configured and set up to implement thefollowing ten operating modes M0 to M9 of the vertical wind turbine 1:

-   -   M0: The vertical wind turbine 1 is switched off in a zeroth        operating mode M0.    -   M1: Start-up readiness of the vertical wind turbine 1 from still        air in a first operating mode M1 at wind speeds below a starting        wind speed v₁, i.e. with 0<v_(W)<v₁, for example where v₁=3 m/s;    -   M2: Start-up of the vertical wind turbine 1 in a second        operating mode M2 at wind speeds above the starting wind speed        v₁ and below a nominal wind speed v₂, i.e. with v₁≤v_(W)<v₂, for        example where v₂=12 m/s;    -   M3: Switching of the vertical wind turbine 1 from a resistance        mode where λ≤1 starting into a fast mode where λ>1 in a third        operating mode M3 or start-up mode at wind speeds above the        starting wind speed v₁ and below a first cut-out wind speed v₃,        i.e. with v₁≤v_(W)<v₃, for example with a minimum rotation speed        of the rotor of 4 [rpm] and a first cut-out wind speed v₃=20 m/s        (average measured over 10 minutes);    -   M4: Shut-down of the vertical wind turbine 1 in a fourth        operating mode M4 at wind speeds above the first cut-out wind        speed v₃ or a further cut-out wind speed v₄, i.e. with v_(W)>v₃        or v_(W)>v₄, respectively, for example where v₄=30 m/s (average        measured over 3 seconds);    -   M5: Restarting of the vertical wind turbine 1 in a fifth        operating mode M5 when the wind speed falls below a restart wind        speed v₅ after a shut-down in the fourth operating mode M4, for        example where v₅=18 m/s;    -   M6: Operation of the vertical wind turbine 1 at a constant tip        speed ratio λ in a sixth operating mode M6 or partial load mode        for wind speeds above the starting wind speed v₁ and below a        nominal wind speed v₂, i.e. with v₁≤v_(W)≤v₂, for example with a        tip speed ratio λ between 2 and 2.6, preferably between 2.2 and        2.4, most preferably 2.3 at a nominal wind speed v₂ of 12 m/s        and a circumferential speed of the blades 7 on the circular path        K of v_(U)=27.6 m/s;    -   M7: Operation of the vertical wind turbine 1 with a variable tip        speed ratio λ in a seventh operating mode M7 or nominal        operation mode or also full-load operation with a nominal speed        of the rotor of for example 16.5 [rpm] at wind speeds above the        nominal wind speed v₂ and below the first cut-out wind speed v₃        or the further cut-out wind speed v₄, i.e. in a nominal wind        speed range with v₂<v_(W)≤v₃ or v₂<v_(W)≤v₄; for example with a        tip speed ratio λ between 1 and 1.8, preferably between 1.3 and        1.5, most preferably 1.38 at a first cut-out wind speed v₃ of 20        m/s;    -   M8: Emergency shut-down of the vertical wind turbine 1 in an        eighth operating mode M8 at extreme wind speed increase        gradients dv_(W)/dt greater than a shut-down gradient of the        wind speed; and    -   M9: Switching-off of the vertical wind turbine 1 in a ninth        operating mode M9 to switch the vertical wind turbine 1 into the        zeroth operating mode from one of the operating modes M1 to M8.

FIG. 12 shows a schematic diagram of a sample torque characteristiccurve of the pitch motor 27. The diagram shows a maximum torque Tp, anominal torque Ti, and continuous torque Tc of the pitch motor 27 overthe rotation speed of the pitch motor 27. The pitch motor 27 can rapidlyproduce the maximum torque Tp in order to spontaneously, i.e. within avery short, extremely limited time, perform a quick adjustment of therespective blade 7. When the maximum torque Tp is exceeded, i.e. when anoverload occurs, the motor slips and is thus inherently safe, i.e. nodamage to the motor occurs. The nominal torque Ti can be usedcontinuously until a temperature limit value is exceeded. As a rule, thecontinuous torque Tc is available on an ongoing basis and does not leadto temperature limit values being exceeded.

FIG. 13 shows a schematic diagram with sample cam disks for controllingthe pitch motor 12, namely a first cam disk S1, which is provided forexample for the nominal wind speed v₂ of for example 12 m/s, and afurther cam disk S2, which is provided for the first cut-out wind speedv₃ of for example 20 m/s. Between these two wind speeds, for example anominal-load operation or full-load operation of the vertical windturbine 1 in the seventh operating mode M7 is provided, in which therotor 2 rotates at a nominal speed and the generator 85 outputs itsnominal power. For each cam disk S1, S2, the set-point value S of thepitch angle β is represented as the set-point pitch angle β_(S) independence of the azimuth angle θ.

At the nominal wind speed v₂, the set-point pitch angle β_(S) at anazimuth angle θ of 0° is less than 0°, for example in the range from −2to −3°. On the way to an azimuth angle θ of 90°, the set-point pitchangle β_(S) first passes through a local maximum of −2 to −3° at anazimuth angle θ of approx. 20° and then passes through an inflectionpoint between −3 and −4° at an azimuth angle θ of approx. 20° until theset-point pitch angle β_(S) at an azimuth angle θ of approx. 50° reachesan absolute minimum of approx. −10°.

At an azimuth angle θ of 180°, the set-point pitch angle β_(S) for thenominal wind speed v₂ is once again approx. 2 to −3° and then, at anazimuth angle θ of approx. 200°, reaches a value of 0°. At an azimuthangle θ of approx. 250°, the set-point pitch angle β_(S) for the nominalwind speed v₂ reaches its absolute maximum of approx. 2 to 3° and thenat an azimuth angle θ of approx. 290° once again reaches a value of 0°and at approximately the same time, passes through an inflection point.Then the set-point pitch angle β_(S) passes through a local minimum ofapprox. −3 to −4° at an azimuth angle θ of approx. 330° and finally, atan azimuth angle θ of approx. 360°, returns once again to its initialrange of −2 to −3°.

At the first cut-out wind speed v₃, the set-point pitch angle β_(S) atan azimuth angle θ of 0° is less than 0°, for example in the range from−1 to −2°, and is thus less than the set-point pitch angle β_(S) at anazimuth angle θ of 0° at a nominal wind speed v₂. On the way to anazimuth angle θ of 90°, without a local maximum, the set-point pitchangle β_(S) passes through an inflection point between −14 and −16° atan azimuth angle θ of approx. 45° until, at an azimuth angle θ ofapprox. 100°, the set-point pitch angle β_(S) passes through anotherinflection point at approx. −30° and then, at an azimuth angle θ ofapprox. 100°, reaches an absolute minimum of approx. −37° to −38°.

At an azimuth angle θ of 180°, the set-point pitch angle β_(S) for thefirst cut-out wind speed v₃, like the set-point pitch angle β_(S) forthe nominal wind speed v₂, is approx. −2 to −3° and then, at an azimuthangle θ of approx. 170°, reaches a value of 0° earlier than theset-point pitch angle β_(S) for the nominal wind speed v₂. At an azimuthangle θ of approx. 230 to 240°, the set-point pitch angle β_(S) reachesits absolute maximum of approx. 35° and then, at an azimuth angle θ ofapprox. 270°, reaches an inflection point at approx. 25°. Then theset-point pitch angle β_(S) passes through an inflection point atapprox. 15° at an azimuth angle θ of approx. 320° and finally, at anazimuth angle θ of approx. 360°, returns once again to its initial rangeof −1 to −2°.

FIG. 14 shows a schematic perspective view of a test bench 200 fordetermining a positioning error of the pitch motor 27 of the verticalwind turbine 1. On the test bench 200, a frame structure 201 isprovided, to which is attached a holding arm 202 for holding the pitchdrive 12 or pitch motor 27 and a transverse arm 203. The pitch drive 12together with a section of the blade 7 is mounted on the holding arm 202of the test bench 200 by means of the motor flange 40 similarly to howit would be mounted to the rotor arm 10 of the vertical wind turbine 1.The transition section 52 protruding out from the pitch motor 27 isaccommodated in a shaft mount 204 of the test bench 200 so that it isable to rotate around the blade rotation axis C₇.

The shaft mount 204 is positioned in the middle of a swing arm 205,which is likewise held so that it is able to rotate around the bladerotation axis C₇ in an extension 206 of the frame structure 201. Aweight 207 is secured at each of the two ends of the swing arm 205oriented away from the blade rotation axis C₇. The weights 207 simulatea total mass of the blade 7. In addition, the ends of the swing arm 205are connected to the transverse arm 203 by means of spring elements 208in the form of coil spring packs and articulating linkages 209 fastenedthereto. The spring elements 208 simulate wind forces.

FIG. 15 shows a schematic diagram of a positioning error, which has beendetermined by means of the test bench 200 shown in FIG. 14, in the forman angular deviation δ of the pitch motor 27 in ° over time tin secondsfor a plurality of control cycles during which a simulated azimuth angleθ passes through a respective rotor rotation of 360°. After an initialtransient response, which does not occur in the vertical wind turbine 1,the angular deviation δ reaches an absolute value of less than 1.5° forset-point pitch angles β_(S) with absolute values of at most 30 to 40°.

FIG. 16 shows a schematic diagram of a positioning error of the pitchmotor 27 in the form of the angular deviation δ in ° over time tinseconds over one control cycle for the nominal wind speed v₂. At anominal wind speed v₂, the angular deviation δ has an absolute value ofalways less than 0.5° and reaches a maximum absolute value of approx.0.25° after respective local and absolute minima and maxima of theset-point pitch angle β_(S). In the vicinity of the inflection points ofthe set-point pitch angle β_(I), the angular deviation δ fluctuatesaround 0°.

FIG. 17 shows a schematic diagram of a positioning error of the pitchmotor 27 in the form of the angular deviation δ in ° over time tinseconds over one control cycle for the first cut-out wind speed v₃. Atthe first cut-out wind speed v₃, the angular deviation δ has an absolutevalue of always less than 1.5° and reaches a maximum absolute value ofapprox. 1.45° after respective local and absolute minima of theset-point pitch angle β_(S) and reaches a maximum of approx. 0.6 atlocal and absolute maxima thereof. In the vicinity of the inflectionpoints of the set-point pitch angle β_(I), the angular deviation δlikewise fluctuates around 0°. In general, therefore, the angulardeviation δ turns out to be slightly higher at the first cut-out windspeed v₃ than at the nominal wind speed v₂.

Deviations from the above-described embodiments and implementationexamples are possible within the scope of the concept of the invention.A person skilled in the art will therefore recognize that characteristicvalues and parameters of the vertical wind turbine 1 and its componentsas well as values for controlling the components are dependent on thedimensions of the vertical wind turbine 1 and are subject to change.Consequently, all of the above-mentioned absolute values of physicalvariables, e.g. wind speeds, are chiefly indicated for a design instanceof the vertical wind turbine 1 described here, with a nominal power of750 KW, a nominal height of 105 m, a rotor diameter of 32 m, a length ofthe blades 7 of 54 m, a height of the blades 7 over the ground of 51 m,a height of the middle of the blades 7 above the ground of 78 m, asurvival wind speed of 59.5 m/s, and an annual average speed of 8.5 m/sand can be varied in accordance with other design instances, which canin turn result in deviations of relative physical variables such as tipspeed ratios.

Also within the scope of the concept of the invention, unlike in theexemplary embodiment described here, more than two pitch drives 12 canbe provided for each blade 7 or, for example, one pitch drive 12 can beprovided for each blade section 13. In other words, two respectiveblades 7 or blade sections 13 can be provided, which are driven in avertically separate way from each other. Thus for example, two pitchdrives 12 can be positioned between two blades 7 or blade sections 13and, as an upper and lower pitch drive 12, can be respectivelyassociated with an upper and lower of the two blades 7 or blade sections13. The upper blade or blade section 13 can thus be rotated around itsblade rotation axis C₇ independently of the lower blade 7 or bladesection 13.

Each of the two blades 7 or blade sections 13 can be associated with atleast one wind speed sensor 104 and/or wind direction sensor 105. The atleast one wind speed sensor 104 and/or wind direction sensor 105 isadvantageously positioned in the middle of the respective blade 7 orblade section 13 and can be mounted on a rod 106 there as describedabove. Consequently, for each of the blades 7 or blade sections 13positioned one above the other vertically, optimal pitch angles β can beseparately set in order to take wind flow conditions that change in thevertical direction Z along the blade 7 into account during operation ofthe vertical wind turbine 1 and thus improve the efficiency of theturbine. This must be taken into consideration particularly for circularpath diameters D_(K) that are larger than 32 m, for example 45 m, inwhich case a total length L₇ of the blades 7 would then be approx. 73 m,for example.

Reference Signs List  1 vertical wind turbine  2 rotor  3 nacelle  4tower system  5 footings  6 switchgear box  7 blade  8 blade mount  9rotor hub  10 rotor arm  10a transverse connecting element  11 signalingand/or measuring mast  12 pitch drive  13 blade section  13a upper endsection  13b upper middle section  13c lower middle section  13d lowerend section  14 bearing point  15 transverse mount  16 transverse struts 17 support structure  18 strut  19 vane  20 arbor  21 bearing unit  22bearing housing  23 rolling bearing  24 bearing shaft  25 motor shaft 26 blade axis  27 pitch motor  28 clearance  29 stator ring  30 rotorring  31 cooling body  32 cooling fins  33 rims  34 clamping set  35motor housing  36 motor interior  37 wall/top  38 wall/bottom  39bearing seat  40 motor flange  40a open space  41 end surface  42mounting flange  43 counterpart end surface  44 connecting element  45reinforcing rib  46 support rib  47 motor bearing  48 bearing receivingchamber  49 sealing element  50 inner ring  51 outer ring  52 transitionsection  53 vane axis section  54 rib  55 connecting end  56 fixingelement  57 flange section  58 positive-fit element  59 furtherconnecting element  60 outer skin  61 casing  62 upper shell  63 lowershell  64 drive gap  65 cooling opening  66 extension  67 end cap  70drive train  71 drive shaft  72 pedestal  73 journal  74 hub shoulder 75 transition ring  76 rotor bearing system  76a first rotor bearing 76b second rotor bearing  76c third rotor bearing  77 bearing bush  78rotor shaft  79 hub connection  80 hub connection  80' hub connection 81 transmission  82 output shaft  83 clutch unit  84 generator shaft 85 generator  86 intended break point  87 transmission housing  88flange bell  89 double-tooth clutch  90 pitch pipe  91 base body  92feed-through  92' feed-through  93 shaft bearing unit  94 supportingfeet  95 rest  96 segment  97 flange end  98 supporting arm  99supporting tab 100 chord line 101 leading edge 102 trailing edge 103counterweight 104 wind speed sensor 105 wind direction sensor 106 rod107 control device 108 supply unit 109 motor control unit 110 powersection 111 choke 112 filter 113 line 114 power supply unit 115 controlunit 116 main power supply unit 117 auxiliary power supply unit 118motor protection unit 119 data transmission unit 120 rotary positiontransducer 121 position sensor 122 motor unit 123 temperature measuringunit 124 temperature sensor 125 other temperature sensor 200 test bench201 frame structure 202 holding arm 203 transverse arm 204 shaft mount205 swing arm 206 extension 207 weight 208 spring element 209articulating linkage i transmission step-up factor d differential valuet time v_(W) wind speed v_(U) circumferential speed v_(R) relative speedv₁ starting wind speed v₂ nominal wind speed v₃ first cut-out wind speedv₄ further cut-out wind speed v₅ restart wind speed A control current B₄maximum width of the tower system C₂ rotor rotation axis C₇ bladerotation axis C₇₁ drive rotation axis D_(K) diameter of the circularpath L₇ length of the blades K circular path I actual value P1resistance force P2 lifting force S set-point value S1 first cam disk S2further cam disk. T temperature measurement value T_(x) othertemperature meas. value Tc continuous torque Ti nominal torque Tpmaximum torque U control value R_(K) radius of the circular path Xlongitudinal direction Y transverse direction Z vertical direction,upward direction α angle of attack β pitch angle β_(I) set-point pitchangle β_(S) actual pitch angle δ angular deviation γ angle of incidenceλ tip speed ratio ⊖ azimuth angle ω angular velocity

1. A vertical wind turbine with a plurality of vertical blades, whichare each fastened to a respective vertical blade axis such that they arepivotable around a respective blade rotation axis independently of oneanother and are supported rotatable on a common circular path around avertical rotor rotation axis, wherein: the vertical wind turbine isconfigured to control a pitch angle of the blades at least in a partialload mode of the vertical wind turbine such that the blades rotate withan essentially constant tip speed ratio.
 2. The vertical wind turbineaccording to claim 1, wherein the vertical wind turbine is designed tooperate in the partial load mode in a range of wind speeds that at leastpartially lie between 3 and 12 m/s.
 3. The vertical wind turbineaccording to claim 1, wherein the constant tip speed ratio amounts tobetween 2 and 2.6, preferably between 2.2 and 2.4, and most preferablyessentially 2.3.
 4. The vertical wind turbine according to claim 1,wherein the vertical wind turbine is configured to control the pitchangle so that in a nominal operation mode of the vertical wind turbine,the blades rotate with a variable tip speed ratio.
 5. The vertical windturbine according to claim 4, wherein the vertical wind turbine isconfigured to control the pitch angle so that in the nominal operationmode, the blades rotate at an essentially constant nominal speed.
 6. Thevertical wind turbine according to claim 4, wherein at a first cut-outwind speed v₃ of the vertical wind turbine, the variable tip speed ratioλ amounts to between 1 and 1.8, preferably between 1.3 and 1.5, mostpreferably essentially 1.38.
 7. The vertical wind turbine according toclaim 1, wherein the vertical wind turbine is configured to control thepitch angle in a start-up mode such that starting from a resistance modewith tip speed ratios of λ≤1, the blades transition into a fast modewith tip speed ratios of λ>1.
 8. The vertical wind turbine according toclaim 1, wherein the control of the pitch angle is based on at least onecam disk, which determines the pitch angle in an essentially continuousmanner for an entire rotation of the rotor.
 9. The vertical wind turbineaccording to claim 1, wherein a maximum value of the pitch angle forwindward positions of the blade is generally greater than for leewardpositions of the blade, with respective regard to the rotor rotationaxis.
 10. The vertical wind turbine according to claim 1, wherein forwind speeds in the range of a nominal wind speed, at an azimuth angle of0° measured from a zero line oriented perpendicularly to the winddirection, the pitch angle is less than zero.
 11. The vertical windturbine according to claim 1, wherein at least for wind speeds in therange of the nominal wind speed, with azimuth angles of 0° to 90°measured from a zero line oriented perpendicularly to the winddirection, there is a local maximum of the pitch angle.
 12. The verticalwind turbine according to claim 1, wherein at least one wind speedsensor and/or at least one wind direction sensor, which is positioned onat least one of the blades and is connected in a signal-transmitting wayto a control device for determining a setpoint of the pitch angle. 13.The vertical wind turbine according to claim 1, wherein at wind speedsfrom still air up to a further cut-off speed of the vertical windturbine, an amount of a positioning error in the control of the pitchangle is essentially always less than 5°, preferably less than 3°, mostpreferably less than 1.5°.
 14. A kit for a vertical wind turbineaccording to claim
 1. 15. A method for operating a vertical windturbine, wherein pitch angles of vertical blades of the vertical windturbine, which are driven around a respective vertical blade axis, arepredetermined, wherein the pitch angle, at least in a partial load modeof the vertical wind turbine, is controlled such that the blades rotatewith an essentially constant tip speed ratio.